This scale was first introduced along with Nakai Tablature in ‘The Art of the Native American Flute’ (1996) by R. Carlos Nakai and James Demars. It has since become the de facto standard for transcribing the contemporary Native American flute.
The Primary scale is effectively the basic scale with one additional pitch. In a number of Nakai's melodies, this extra pitch provides the tension or sorrow of the melody.
Additional pitches make up Nakai's extended scale.